The present invention relates to fuel cell technology. In particular, the invention relates to systems and methods for improving the thermal efficiency of a fuel cell system.
A fuel cell electrochemically combines hydrogen and oxygen to produce electricity. The ambient air readily supplies oxygen; hydrogen provision, however, calls for a working supply. The hydrogen supply may include a direct hydrogen supply or a ‘reformed’ hydrogen supply. A direct hydrogen supply employs a pure source, such as compressed hydrogen in a pressurized container, or a solid-hydrogen storage system, such as a metal-based hydrogen storage device.
A reformed hydrogen supply processes a fuel (or fuel source) to produce hydrogen. The fuel acts as a hydrogen carrier, is manipulated to separate hydrogen, and may include a hydrocarbon fuel, hydrogen bearing fuel stream, or any other hydrogen fuel such as ammonia. Currently available hydrocarbon fuels include methanol, ethanol, gasoline, propane and natural gas. Liquid fuels offer high energy densities and the ability to be readily stored and transported.
Consumer electronics devices and other portable electrical power applications currently rely on lithium ion and other battery technologies. Portable fuel cell systems that generate electrical energy for portable applications such as electronics devices would be desirable but are not yet commercially available.
Thermal inefficiencies in a portable fuel cell system waste energy and undesirably require more fuel to be consumed and carried. Techniques that increase efficiency of a portable fuel cell system would be beneficial.